EngRocker Arm Nut, 3/8" Adjusting Nut Set Magnum Rockers, See 1400N-1 for individual adjusting nut., Replacement Adjusting Nut Set for Magnum Rockers w/ 3/8" Stud, None, The 1400N-16 adjusting nuts replace the nuts that come with our 3/8" stud Magnum roller tip rockers., Engine Rocker Arm Nut.